This invention relates to a device and method for puncturing a selected layer or layers of the skin or mucosa. More particularly, the invention relates a device and method for puncturing the stratum corneum or mucosa to diminish the barrier function thereof and permit a drug to be delivered to the body or an analyte in the body to be withdrawn for monitoring. This puncturing of the stratum corneum or mucosa is minimally invasive, and can be combined with various other methods, such as use of chemical enhancers, pressure gradients, sonic gradients, temperature gradients, and the like for selectively enhancing the inward flux of a drug to the body or the outward flux of an analyte from the body.
The stratum corneum is chiefly responsible for the well-known barrier properties of skin. Thus, it is this layer of the skin that presents the greatest barrier to transdermal flux of drugs or other molecules into the body and of analytes out of the body. Mucosal tissue also presents a barrier to flux of molecules into and out of the body. The stratum corneum, the outer horny layer of the skin, is a complex structure of compact keratinized cell remnants separated by lipid domains. Compared to the oral or gastric mucosa, the stratum corneum is much less permeable to molecules either external or internal to the body. The stratum corneum is formed from keratinocytes, which comprise the majority of the epidermal cells, that lose their nuclei and become corneocytes. These dead cells comprise the stratum corneum, which has a thickness of about 10-30 .mu.m and, as noted above, is a very resistant waterproof membrane that protects the body from invasion by exterior substances and the outward migration of fluids and dissolved molecules. The stratum corneum is continuously renewed by shedding of corneum cells during desquamination and the formation of new corneum cells by the keratinization process.
Various methods of enhancing the permeability of the stratum corneum and mucosa have been described. For example, U.S. Pat. No. 5,458,140 and U.S. Pat. No. 5,445,611 disclose using ultrasonic energy that is modulated in intensity, phase, or frequency or a combination thereof. U.S. Pat. No. 4,775,361 discloses a method of administering a drug by ablating the stratum corneum using pulsed laser light without significantly damaging the underlying epidermis. Numerous patents teach the use of chemical enhancers for improving transdermal flux of a drug through the skin. E.g, U.S. Pat. No. 4,863,970. It would be advantageous to develop additional methods of permeating the stratum corneum or mucosa to enhance the transport of drugs into the body or analytes out of the body, particularly without the need for expensive or complicated equipment.
In view of the foregoing, it will be appreciated that providing a device and method of use thereof for introducing multiple micropores or perforations in the stratum corneum or mucosa for enhancing transport of molecules therethrough would be a significant advancement in the art.